Spastic quadriplegia-52 is an autosomal recessive neurodevelopmental disorder characterized by neonatal hypotonia that progresses to hypertonia and spasticity and severe mental retardation with poor or absent speech development (summary by Abou Jamra et al., 2011).
Abou Jamra et al. (2011) reported a consanguineous Syrian kindred (MR061) in which 5 individuals had severe mental retardation and spasticity. They had delayed motor development in infancy, but lost the ability to walk in early childhood due ... Abou Jamra et al. (2011) reported a consanguineous Syrian kindred (MR061) in which 5 individuals had severe mental retardation and spasticity. They had delayed motor development in infancy, but lost the ability to walk in early childhood due to spasticity. Physical examination showed muscular hypertonia, especially of lower limbs, contractures, talipes equinovarus, decreased shank muscle mass, short stature, and microcephaly. All had a severe cognitive deficit and absent speech and could only express basic needs. Dysmorphic features included a prominent and bulbous nose, wide mouth, and coarse features. All were markedly shy, amicable, and calm, and kept smiling or laughing for no obvious reason, but did not have laughter bursts. None of the patients had seizures, a hearing impairment, or any anomalies of inner organs.
By linkage analysis followed by candidate gene sequencing of a Syrian family with autosomal recessive mental retardation and spasticity, Abou Jamra et al. (2011) identified a homozygous truncating mutation in the AP4S1 gene (607243.0001). The authors concluded that ... By linkage analysis followed by candidate gene sequencing of a Syrian family with autosomal recessive mental retardation and spasticity, Abou Jamra et al. (2011) identified a homozygous truncating mutation in the AP4S1 gene (607243.0001). The authors concluded that AP4-complex-mediated vesicular trafficking plays a crucial role in brain development and function.